A small utility application to convert android adb backup to tgz archive which can be opened with 7zip or any other zip utilities.
Download the application from release section on right side bar of this page.
Drag your adb file on top of adb2tgz.exe or use following command line in console.
adb2tgz.exe {path to your adb backup file}
Once the process is complete adb file will be renamed to tgz.
Due to normally large size of adb backup files, this utility will not create a second file and will modify original file. Running this utility on your adb more than once might corrupt it, Make a backup from your adb file before using this.